Auxiliary diagnosis devices include Magnetic Resonance (MR) systems, ultrasonic systems, X-ray computed tomography systems, X-ray positron emission tomography (PET) systems, nuclear medical and other types of imaging systems.
For example, when a CT system is adopted to conduct X-ray CT imaging of a patient, X-rays are used for imaging of features of internal structures and regions of interest (ROI) of the patient's body. The imaging is completed by a CT scanner. During operation, scanning is conducted to the object to be photographed and raw data is collected, and then an image is reconstructed according to the raw data.
Objects having a high X-ray absorption property, such as metal substances, will cause artifacts in the reconstructed CT images, and affect diagnosis results. For example, metal dentures, artificial joint, biopsy needles, surgical clips, etc. will generate thin line-shaped or radiant lights during the reconstruction process of images.
These artifacts can be reduced through the existing Metal Artifact Reduction (MAR) techniques. However, some existing metal artifact reduction techniques may suffer from the problems of possibly decreasing resolution of images while reducing artifacts. Or, the problem of resolution is taken into consideration, but there possibly exist the problem of metal artifacts, such as white-band artifacts.